将动态权限的检查封装到插件库中

android/src/main/AndroidManifest.xml

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.zt.shareextend">
 
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+
     <application>
 
         <provider

android/src/main/java/com/zt/shareextend/ShareExtendPlugin.java

@@ -2,13 +2,19 @@ package com.zt.shareextend;
 
 import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
+import io.flutter.plugin.common.PluginRegistry;
 import io.flutter.plugin.common.PluginRegistry.Registrar;
 
+import android.Manifest;
 import android.content.Context;
 import android.content.Intent;
 
+import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Build;
+import android.os.Environment;
+import android.support.v4.app.ActivityCompat;
+import android.support.v4.content.ContextCompat;
 import android.support.v4.content.FileProvider;
 
 
@@ -18,19 +24,24 @@ import java.util.Map;
 /**
  * Plugin method host for presenting a share sheet via Intent
  */
-public class ShareExtendPlugin implements MethodChannel.MethodCallHandler {
+public class ShareExtendPlugin implements MethodChannel.MethodCallHandler, PluginRegistry.RequestPermissionsResultListener {
 
+    /// the authorities for FileProvider
     private static final String authorities = "com.zt.shareextend.fileprovider";
-
+    private static final int CODE_ASK_PERMISSION = 100;
     private static final String CHANNEL = "share_extend";
 
+    private final Registrar mRegistrar;
+    private String text;
+    private String type;
+
     public static void registerWith(Registrar registrar) {
         MethodChannel channel = new MethodChannel(registrar.messenger(), CHANNEL);
-        ShareExtendPlugin instance = new ShareExtendPlugin(registrar);
+        final ShareExtendPlugin instance = new ShareExtendPlugin(registrar);
+        registrar.addRequestPermissionsResultListener(instance);
         channel.setMethodCallHandler(instance);
     }
 
-    private final Registrar mRegistrar;
 
     private ShareExtendPlugin(Registrar registrar) {
         this.mRegistrar = registrar;
@@ -54,6 +65,8 @@ public class ShareExtendPlugin implements MethodChannel.MethodCallHandler {
         if (text == null || text.isEmpty()) {
             throw new IllegalArgumentException("Non-empty text expected");
         }
+        this.text = text;
+        this.type = type;
 
         Intent shareIntent = new Intent();
         shareIntent.setAction(Intent.ACTION_SEND);
@@ -62,6 +75,14 @@ public class ShareExtendPlugin implements MethodChannel.MethodCallHandler {
             shareIntent.putExtra(Intent.EXTRA_TEXT, text);
             shareIntent.setType("text/plain");
         } else {
+
+            if (isPathInExternalStorage(text)) {
+                if (!checkPermisson()) {
+                    requestPermission();
+                    return;
+                }
+            }
+
             File f = new File(text);
             Uri uri = getUriForFile(mRegistrar.context(), f);
             if ("file".equals(type)) {
@@ -82,8 +103,32 @@ public class ShareExtendPlugin implements MethodChannel.MethodCallHandler {
         }
     }
 
+    private boolean isPathInExternalStorage(String path) {
+        File storagePath = Environment.getExternalStorageDirectory();
+        return path.startsWith(storagePath.getAbsolutePath());
+    }
+
+    private boolean checkPermisson() {
+        if (ContextCompat.checkSelfPermission(mRegistrar.context(), Manifest.permission.READ_EXTERNAL_STORAGE)
+                == PackageManager.PERMISSION_GRANTED) {
+            return true;
+        }
+        return false;
+    }
+
+    private void requestPermission() {
+        ActivityCompat.requestPermissions(mRegistrar.activity(), new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, CODE_ASK_PERMISSION);
+    }
+
+    @Override
+    public boolean onRequestPermissionsResult(int requestCode, String[] perms, int[] grantResults) {
+        if (requestCode == CODE_ASK_PERMISSION && grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+            share(text, type);
+        }
+        return false;
+    }
 
-    public static Uri getUriForFile(Context context, File file) {
+    private static Uri getUriForFile(Context context, File file) {
         if (Build.VERSION.SDK_INT >= 24) {
             return FileProvider.getUriForFile(context, authorities, file);
         } else {

example/lib/main.dart

@@ -3,7 +3,6 @@ import 'dart:io';
 
 import 'package:share_extend/share_extend.dart';
 import 'package:image_picker/image_picker.dart';
-import 'package:permission/permission.dart';
 import 'package:path_provider/path_provider.dart';
 
 void main() => runApp(new MyApp());
@@ -43,21 +42,11 @@ class _MyAppState extends State<MyApp> {
               },
               child: new Text("share image"),
             ),
-            new RaisedButton(
-              onPressed: () async {
-                File f =
-                    await ImagePicker.pickImage(source: ImageSource.gallery);
-                ShareExtend.share(f.path, "file");
-              },
-              child: new Text("share file"),
-            ),
             new RaisedButton(
               onPressed: () {
-                if (Platform.isAndroid) {
-                  _shareFileWithPerm();
-                }
+                _shareApplicationDocumentsFile();
               },
-              child: new Text("share android external storage file"),
+              child: new Text("share file"),
             ),
           ],
         )),
@@ -65,44 +54,14 @@ class _MyAppState extends State<MyApp> {
     );
   }
 
-  /// share the external storage file ,first check the permission
-  _shareFileWithPerm() async {
-    if (await _checkPermission()) {
-      _shareFile();
-    } else {
-      var result = await _requestPermission();
-
-      /// to ask for permission
-      if (result == PermissionStatus.allow) {
-        _shareFile();
-      }
-    }
-  }
-
-  /// create a test file for the share example
-  _shareFile() async {
-    String filePath = await _createTestFileToShare();
-    ShareExtend.share(filePath, "file");
-  }
-
-  ///create a test file to share
-  _createTestFileToShare() async {
-    Directory storageDir = await getExternalStorageDirectory();
-    File testFile = new File("${storageDir.path}/flutter/test.txt");
+  ///share the documents file
+  _shareApplicationDocumentsFile() async {
+    Directory dir = await getApplicationDocumentsDirectory();
+    File testFile = new File("${dir.path}/flutter/test.txt");
     if (!await testFile.exists()) {
       await testFile.create(recursive: true);
+      testFile.writeAsStringSync("test for share documents file");
     }
-    testFile.writeAsStringSync("test for share");
-    return testFile.path;
-  }
-
-  _checkPermission() async {
-    List<Permissions> perms =
-        await Permission.getPermissionStatus([PermissionName.Storage]);
-    return perms[0].permissionStatus == PermissionStatus.allow;
-  }
-
-  _requestPermission() async {
-    return await Permission.requestSinglePermission(PermissionName.Storage);
+    ShareExtend.share(testFile.path, "file");
   }
 }

example/pubspec.yaml

@@ -21,8 +21,6 @@ dependencies:
   cupertino_icons: ^0.1.2
   image_picker: ^0.4.10
   path_provider: ^0.4.1
-  permission: ^0.1.0
-
 
 dev_dependencies:
   flutter_test: